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Reionization effective likelihood from Planck 2018 data

Heinrich, Chen and Hu, Wayne (2021) Reionization effective likelihood from Planck 2018 data. Physical Review D, 104 (6). Art. No. 063505. ISSN 2470-0010. doi:10.1103/PhysRevD.104.063505.

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We release RELIKE (reionization effective likelihood), a fast and accurate effective likelihood code based on the latest Planck 2018 data that allows one to constrain any model for reionization between 6 < z < 30 using five constraints from the CMB reionization principal components (PC). We tested the code on two example models which showed excellent agreement with sampling the exact Planck likelihoods using either a simple Gaussian PC likelihood or its full kernel density estimate. This code enables a fast and consistent means for combining Planck constraints with other reionization data sets, such as kinetic Sunyaev-Zeldovich effects, line-intensity mapping, luminosity function, star formation history, quasar spectra, etc., where the redshift dependence of the ionization history is important. Since the PC technique tests any reionization history in the given range, we also derive model-independent constraints for the total Thomson optical depth τ_(PC) = 0.0619^(+0.0056)_(−0.0068) and its 15 ≤ z ≤ 30 high redshift component τ_(PC_(15,30) < 0.020 (95% C.L.). The upper limits on the high-redshift optical depth is a factor of ∼3 larger than those reported in the Planck 2018 cosmological parameter paper using the FlexKnot method and we validate our results with a direct analysis of a two-step model which permits this small high-z component.

Item Type:Article
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URLURL TypeDescription Paper
Heinrich, Chen0000-0003-0426-1948
Alternate Title:RELIKE: Reionization Effective Likelihood from Planck 2018 Data
Additional Information:© 2021 American Physical Society. Received 11 May 2021; accepted 14 July 2021; published 2 September 2021. We thank Tzu-Ching Chang, GuoChao Sun, Lluis Mas-Aribas and Olivier Doré for useful discussions. W. H. was supported by U.S. Dept. of Energy Contract No. DE-FG02-13ER41958 and the Simons Foundation.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-13ER41958
Simons FoundationUNSPECIFIED
Issue or Number:6
Record Number:CaltechAUTHORS:20210825-184638673
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110561
Deposited By: George Porter
Deposited On:30 Aug 2021 17:24
Last Modified:02 Sep 2021 20:29

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